Environmental Chemistry

Step 1: Minamata Disease Overview.
Minamata disease is a neurological syndrome caused by severe mercury (Hg) poisoning. It was first identified in Minamata Bay, Japan, where industrial discharge of mercury into the bay contaminated the local seafood, leading to widespread mercury poisoning among the population.

Step 2: Conclusion.
Minamata disease is caused by mercury (Hg) poisoning, which corresponds to option (4).